Talles LJust add another reference under <packageSources> on ~/.nuget/NuGet/NuGet.config (or %appdata%\NuGet\NuGet.Config on Windows):
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<packageSources>Alt Text
<add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
<add key="Home directory" value="/home/john/NuGet" />
</packageSources>
</configuration>
Or edit through the "Package Sources" option on Visual Studio:
